Effect of the Correlation Properties of One- and Three-Dimensional Inhomogeneities on the High-Frequency Magnetic Susceptibility of Sinusoidal Superlattices

Abstract

The effect of one-(1D) and three-dimensional (3D) inhomogeneities on the high-frequency magnetic susceptibility at the boundary of the first Brillouin zone of a ferromagnetic superlattice is studied. The study is performed with an earlier developed method of random spatial modulation (RSM) of the superlattice period. In this method, structural inhomogeneities are described in terms of the random-phase model, in which the phase depends on three coordinates in the general case. The frequency spacing Δνm between two peaks in the imaginary part of the averaged Green’s function, which characterizes the gap width in the frequency spectrum at the boundary of the Brillouin zone, is calculated as a function of both the root-mean-square fluctuations γi and the correlation wavenumbers ηi of phase inhomogeneities (i = 1 and 3 for 1D and 3D inhomogeneities, respectively). The function Δνm(γ1, η1) for 1D inhomogeneities is shown to be symmetric with respect to interchanging the variables γ 1 2 and η1, whereas the function Δνm(γ3, η3) for 3D inhomogeneities is strongly asymmetric with respect to interchanging γ 2 3 and η3. This effect is associated with the difference in form between the correlation functions of 1D and 3D inhomogeneities and can be used to determine the dimensionality of inhomogeneities from the results of spectral studies of such superlattices.